/b-gtk/fix-viz

# -*- coding: UTF-8 -*-

"""Directed graph production.

This module contains the code to produce an ordered directed graph of a

bzr branch, such as we display in the tree view at the top of the bzrk

window.

"""

__copyright__ = "Copyright © 2005 Canonical Ltd."

__author__    = "Scott James Remnant <scott@ubuntu.com>"

from bzrlib.revision import Revision

from bzrlib.tsort import merge_sort

def linegraph(revisions, revisionparents, revindex):

    """Produce a directed graph of a bzr branch.

    Returns a list of tuples of (revision, node, lines, parents, children).

    Node is a tuple of (column, colour) with column being a zero-indexed

    column number of the graph that this revision represents and colour

    being a zero-indexed colour (which doesn't specify any actual colour

    in particular) to draw the node in.

    Lines is a list of tuples which represent lines you should draw away

    from the revision, if you also need to draw lines into the revision

    you should use the lines list from the previous iteration.  Each

    typle in the list is in the form (start, end, colour) with start and

    end being zero-indexed column numbers and colour as in node.

    It's up to you how to actually draw the nodes and lines (straight,

    curved, kinked, etc.) and to pick the actual colours for each index.

    """

    directparentcache = [None for revision in revisions]

    def getdirectparent(childindex, childsparents):

        """Return the revision id of the direct parent

        The direct parent is the first parent with the same committer"""

        childrevision = revisions[childindex]

        directparent = directparentcache[childindex]

        if directparent is None:

            for parentrevid in childsparents:

                parentrevision = revisions[revindex[parentrevid]]

                if childrevision.committer == parentrevision.committer:

                    directparent = parentrevid

                    break

            #no parents have the same commiter

            if directparent is None:

                directparent = ""

            directparentcache[childindex] = directparent

        return directparent

    #This will hold the lines we have not yet added to lines

    #The position of the item in this list indicates the column, and it

    #it may change if we need to make space for other branches.

    #Each typle in the list is in the form (child index, parent revision)

    #A item may be None to indicate that there is no line for a column

    activelines = []

    linegraph = []

    lastcolor = 0

    for (index, revision) in enumerate(revisions):

        parents = [parent for parent in revisionparents[index]\

                   if parent!="null:"]

        revnodecolumn = None

        #This will hold a list of lines whose parent is this rev

        linesforcurrentrev = []

        children = []

        #We should maybe should pop None's at the end of activelines.

        #I'm not sure what will cost more: resizing the list, or

        #have this loop ittrate more.

        #Find lines that end at this rev

        for (column, activeline) in enumerate(activelines):

            if (activeline is not None):

                (childindex, parentrevid) = activeline

                if parentrevid == revision.revision_id:

                    linesforcurrentrev.append((childindex, parentrevid, column))

                    activelines[column] = None

                    children.append(linegraph[childindex][0].revision_id)

                    #The node column for this rev will be the smallest

                    #column for the lines that end at this rev

                    #The smallest column is the first one we get to.

                    if revnodecolumn is None:

                        revnodecolumn = column

        #This will happen for the latest revision

        if revnodecolumn is None:

            revnodecolumn = 0

        color = None

        #Try and see if we are the same "branch" as one of our children

        #If we are, use the childs color

        for childrevid in children:

            childindex = revindex[childrevid]

            childsparents = revisionparents[childindex]

            if len(children) == 1 and len(childsparents) == 1: 

                # one-one relationship between parent and child, same colour

                #1st [1] selects the node

                #2nd [1] selects the color

                color = linegraph[childindex][1][1]

                break

            #Is the current revision the direct parent of the child?

            if revision.revision_id == getdirectparent(childindex, childsparents):

                color = linegraph[childindex][1][1]

                break

        if color is None:

            color = lastcolor = lastcolor + 1

        #We now have every thing (except for the lines) so we can add

        #our tuple to our list.

        linegraph.append((revision, (revnodecolumn, color),

                          [], parents, children))

        #add all the line bits to the rev that the line passes

        for (childindex, parentrevid, column) in linesforcurrentrev:

            if index>childindex+1:

                #out from the child to line

                linegraph[childindex][2].append(

                    (linegraph[childindex][1][0], #the column of the child

                     column,                      #the column of the line

                     color))

                #down the line

                for linepartindex in range(childindex+1, index-1):

                    linegraph[linepartindex][2].append(

                        (column,                  #the column of the line

                         column,                  #the column of the line

                         color))

                #in to the parent

                linegraph[index-1][2].append(

                    (column,                      #the column of the line

                     revnodecolumn,               #the column of the parent

                     color))

            else:

                #child to parent

                linegraph[childindex][2].append(

                    (linegraph[childindex][1][0], #the column of the child

                     revnodecolumn,               #the column of the parent

                     color))

        for parentrevid in parents:

            column = revnodecolumn

            line = (index,parentrevid)

            while True:

                if column<len(activelines):

                    if activelines[column] is None:

                        #An empty column. Put line here

                        activelines[column] = line

                        break

                    else:

                        if activelines[column][0] == index:

                            #This column is allready used for a line for

                            #this rev, Move along.

                            column += 1

                        else:

                            #This column is allready used for a line for

                            #another rev. Insert this line at this column,

                            #and in the process, move all the other lines out.

                            activelines.insert(column, line)

                            break

                else:

                    #no more columns, so add one to the end

                    activelines.append(line)

                    break

    return linegraph

def same_branch(a, b):

    """Return whether we think revisions a and b are on the same branch."""

    if len(a.parent_ids) == 1:

        # Defacto same branch if only parent

        return True

    elif a.committer == b.committer:

        # Same committer so may as well be

        return True

    else:

        return False